History records that Honda quit Formula 1 at the end of the 2008 season, but Japanese engineers continued to work in secret and were very advanced on a 2009 car design and beyond. Ultimately this secret R&D project lead to the firm creating a 2014 specification hybrid power unit which will be used by McLaren in 2015 but in between some fascinating work was conducted.
(Racecar Engineering takes an indepth look at the Honda RA109, the car Honda was going to enter in F1 in 2009 before they pulled out. As you'll see, this car is not just the Brawn BGP001 that emerged from the ashes of Honda Racing F1, but is actually its own innovative design.)
When Honda quit Formula 1 at the end of the 2008 season the prospects for the team behind it based at Brackley were bleak. Through the winter Ross Brawn called in all the favours available and a few more to put a new team together. Using the unfinished 2009 Honda designs as a basis the new team pushed ahead. This was not a straightforward task, the Brawn team used a Mercedes V8 engine instead of the Honda V8 that the car had initially been designed for, meaning that the rear of the monocoque had to be changed significantly. History records that Brawn BGP001 won both drivers and constructors titles in 2009 before the team morphed into Mercedes GP.
Rarely is anything discussed about the Honda RA109, the general understanding being that the car became the Brawn BGP001 and to an extent that is true, but there was still a distinct and separate RA109 design which is revealed in this article.
During Honda's whole '3rd era' F1 project it had multiple R&D teams working on car design. In reality there were three main Honda development teams, the main one being at the Honda F1 team in Brackley, England, but in addition to that there was Honda R&D in Tochigi, Japan and finally the smaller HRD facility in Bracknell, England which was primarily concerned with the engines.
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When Honda decided to withdraw from F1, the R&D department at Brackley stopped work, when it restarted it was focussed on creating the Brawn BGP001, but the R&D team in Tochigi had continued with the RA109 for much longer than anyone realised.
Honda RA109: Overview
The Honda RA109 was on the face of it a conventional 2009 car design as this wind tunnel model shows. It has pushrod front and rear suspension, the simplified bodywork as mandated by the 2009-2013 aerodynamic regulations, complete with wide front wing and narrow rear. The power would have of course come from Honda's V8 F1 engine and the transmission would have been a seven speed seamless shift unit. A quick look at the wind tunnel model above (thought to be in the DOME wind tunnel) reveals that the overall design of the RA109 is visually quite different to the Brawn BGP001.
Honda RA109 Aerodynamic development
This section of the article was created with the assistance of Sans Inc
Honda conducted more than one wind tunnel programme during its '3rd Era' activities. The Honda F1 Team in Brackley, England had two tunnels on site, while a third tunnel at Dome in Japan is also thought have been used. It is at the latter where it is thought that the Honda R&D engineers developed the RA109, even after the Brackley facility had turned into Brawn GP.
The RA109 is immediately distinct to the BGP001 when looking at the design of the nose cone, whilst the BGP001 had a relatively low wide nose (below), the RA109 had a much smaller narrow nose.
The nose was a major area of focus for the Honda engineers who felt the need to evaluate many different shapes and design concepts. The overall front wing design seems fairly basic compared to that of the Brawn but far more advanced concepts were on the drawing board.
The image above shows the sheer range of nose shapes evaluated by Honda R&D none of which are similar to that used by Brawn, though the shape on the top left P1(min) was clearly the preferred option for the RA109. Interestingly inspecting the nose shape of the RA109 model and the BGP001 racecar you notice that the front of the monocoque appears to be different, suggesting that the rather than the definitive Honda RA109 the tunnel model may actually be that of the RA1089, the interim test car seen in late 2008 (below).
On inspection the Honda RA108 was used for the nose shape evaluations, but not for the wind tunnel model which features a few notable differences including the suspension position both internal and external (note the blisters on the top of the chassis). The front wing and wing supports though were tested on track in November 2008 on the RA1089. One of the reasons that the nose was so critical to the shape of the front of the RA109, will become clear in the mechanical development section of this article (section 3) but it also suggests that it was not only the rear of the Brawn BGP001 that was modified from the RA109 design but also the front bulkhead.
One curious area of development for the RA109 was the winged nose concept, first seen on the RA108 in the form of 'bunny ears' the RA109 may have also featured similar elements.
The design above was one of the favoured options after wind tunnel testing by Honda R&D in Japan, and various iterations of it were tried in both CFD and also in the wind tunnel suggesting that Honda felt that the concept was legal. One version (below) included a small turning vane between the two blades.
But Honda Racing F1 Team in Brackley clearly favoured a wider lower nose, which it had fitted to its model. It also tried out some concepts for aerodynamic parts on the nose.
An early concept was really a continuation of the bunny ear ideas, but it seems that this was discarded in favour of the nose fins (below) similar but not identical to those tried in Japan.
That design was tuned with a number of different leading and trailing edges. It was this model and not the one with the narrower front used in Japan that was inherited by Brawn, the beginnings of BGP001′s wide nose can be seen (below)
Not all of the focus on the RA109 model was on the front of the car, there are some interesting details around the middle of the car that highlight the differences between it and the BGP001. Some of these are due to the change of engine supplier. The Mercedes and Honda V8′s would have had different demands in terms of cooling and combustion air. This can be seen when looking at the roll hoop area of the RA109 and comparing it with the BGP001.
The Honda airbox (above) looks to be a direct carry over from the RA108, this is not a great surprise as the engine was essentially in a frozen specification and its demands would not have changed, but the Brawn intake is quite different, having to cater to the Mercedes V8 (below). The roll hoop shape is as a result entirely different to that of the RA108 & RA109.
The cooling requirements between the two engines also differed the RA109 had relatively small almost square cooling ducts on the sidepods feeding the water and oil coolers with air (below) note the turning vane on the side of the chassis (with helpful arrow)
The Brawn on the other hand had much wider elongated ducts (below), which look somewhat higher and less compact, perhaps as a result of the cars very rapid transition from Honda to Brawn. Or perhaps due to the different demands of the German engine.
In 2009 the big story was one of aerodynamics, in particular the rear of the cars. Three teams Brawn, Toyota and Williams had exploited a loophole in the regulations that saw them increase the area of the diffusers to a level mach greater than the rule makers anticipated. It was one of the main reasons that the Brawn team was so strong in the first half of 2009.
It is no secret that Honda was fully aware of this loophole in the rules too, and had developed its own double deck diffuser, separate to the one used on the BGP001, although visually cruder. More advanced and complex versions were also developed by Honda R&D.
The rear of the car is an area where the Japanese engineers felt that there were gains to be made and they came up with a range of nice detail solutions including the so called 'dumbbell' cooling exit on the rear of the car (below)
From the rear the exhaust exits on the RA109 are clear to see, this is one area where you may expect to find significant difference to the Mercedes powered Brawn.
On the Honda design (above) the exhaust exits are located a lot further forward than those on the Brawn (below) interestingly the Brawn team had to change its design after winning the Australian Grand Prix after it was found to be slightly outside the regulations.
So just how far did the aerodynamic development really go? that much is not clear, but it is suspected that the R&D continued deep into 2009 and perhaps beyond. It is thought that Honda developed its own blown diffuser in 2011 simply in order to understand the technology behind it but the details of that and other projects at Tochigi are still kept firmly under wraps.
Tantalisingly however some details of aerodynamic development from 2009 have been revealed, a slide from an internal presentation details part of the update kit for the 2009 Australian Grand Prix, with a new rear wing. Dubbed URW669 it was developed to achieve 1.35-1.25 drag level and could be rotated by 15 degrees. Overall the wing was more efficient and gave 6 points less drag than the launch/test spec wing.
But the update kit, new wing and other parts were never seen on the car as it never took to the track. However under the skin there were many fascinating mechanical details some of which are revealed in part 3.
Honda RA109 Mechanical development
The development of the 2009 car was not just limited to aerodynamic research, the engineers in Tochigi had also designed a very compact and lightweight differential for the RA109. The new unit was 1.2kg lighter and its size allowed it to be repositioned in the transmission.
This would have reduced the cars inertial moment by 0.3% and lowered the centre of gravity by 1.1mm. The work saw the distance between the final drive shafts reduced from 125mm to 100mm and tests proved that the new design could last at least four races. The 'Ultra Short Differential' or USD was not used by Brawn GP.
The RA109 differential compared to the RA108 differential shows how much more compact the 2009 design was. The transmission was a major area of development for Honda, and the RA109 was to feature an innovative new gearbox. A new concept was developed that saw the engineers focus on reducing the length of the gear ratio portion of the 'box, using the idea of eliminating the dog ring and shift fork between the gears. The target was to reduce gearbox length by 19% (192.7mm down to 155.1mm) and weight by 12% (from 10.4kg down to 9.1kg). It would be achieved by putting the shifting components inside the main shaft and aligning the ratios with no gap.
A gearbox using the concept was built and run on the test bench where it achieved its targets. As it was ready to be fitted to a car and tested on track using the Honda RA1089 chassis the company announced its withdrawal from the sport and the design remains unproven.
Hybrid / KERS
Honda initially investigated a flywheel based KERS but later opted for a Li-ion based battery electric KERS for the 2009 season. The car designed to be fitted with it became known as the Honda RA109K. Unusually it was to have the battery pack positioned under the nose of the car, where most teams placed the energy store either under the fuel tank or around the bell housing (Red Bull).
It experimented with a number of solutions in terms of MGU position and overall system performance. The first iteration tried on track was fitted to RA108 chassis 2 and had the MGU mounted on the transmission, the battery under the fuel cell.
As with all of its 2009 KERS solutions the Honda system, which was developed in house, produced 60kW power and just 45Nm torque. Later the battery cells were relocated under the nose and the MGU onto the front of the engine, a unique layout. But an interim version of this layout did see track time, Anthony Davidson clocked up 44km in the KERS equipped Honda RA1089 (complete with nose mounted batteries) at Kemble and Santa Pod. RA109K was scheduled to test in January 2009, and Honda fully expected to run the system all season long. A full detailed article on the Honda KERS will appear on this site in a few days time.
Honda Formula 1 4th Era
As Honda is about to move into its 4th era of Formula 1 activity it must be contemplating the lessons of the past. The RA109 could have set a new benchmark in Formula 1, as it would have been packed with innovative design features, and the car is spawned, the Brawn BGP001 went on to win both titles something Honda badly wanted. If Honda had not pulled out of Formula 1 would it have been as successful as Brawn, or perhaps even more successful? It is impossible to say, but perhaps the RA109 was a step too far, too much advanced technology and complex a design. Nobody will ever know.
The free thinking engineers at Tochigi who came up with the RA109 in conduction with the engineers in Brackley had obviously not been given many limits on what was possible. Note this design (above and below) called the O-nose from a few years earlier when the team was still BAR-Honda.
With Honda about to open its new UK racing facility in Milton Keynes (below) it is hard to imagine that the engineers in Tochigi (themselves with a new facility) will not want to get involved in developing the whole car again and not just the power unit. How well this will be received at McLaren is another question
This story was originally published on Racecar Engineering on 6/26/2014 and has been syndicated here with permission. If you'd like your work to be considered for syndication, send an email to 'firstname.lastname@example.org' with the subject line "Syndication."
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